Hydrocarbons can be produced through a wellbore traversing a subterranean formation. In some cases, the formation may be unconsolidated or loosely consolidated. Particulate materials, such as sand, from these types of formations may be produced together with the hydrocarbons. Production of particulate materials presents numerous problems. Examples of problems include particulate materials being produced at the surface, causing abrasive wear to components within a production assembly, partially or fully clogging a production interval, and causing damage to production assemblies by collapsing onto part or all of the production assemblies.
Sand control screens can be used to provide stability to a formation to prevent or reduce collapses and to filter particulate materials from hydrocarbon fluids. In a typical sand control screen implementation, such as a gravel or “frac” pack, a completion assembly is run on a service tool downhole. The completion assembly includes a screen, shear sub, blank pipe, a packer assembly, and a bull plug or sump packer seal assembly. The packer is set and the completion assembly is released from the packer. The service tool is manipulated to obtain proper positioning to control fluid flow downhole.
For example, the service tool can be manipulated into a “circulating, live-annulus position” to allow fluid slurry to be pumped into the annulus area formed between the screen and the base pipe. The slurry can include a liquid carrier and particulate material, such as gravel or other proppant. The flow path for slurry to be pumped downhole can include a work string, a crossover port in the completion assembly, a closing sleeve port in the assembly, and a lower annulus between the screen and the base pipe. The particulate material can be deposited in the lower annulus area to form a gavel pack. The gravel pack can be highly permeable for the flow of hydrocarbon fluids but can block the flow of the fine particulate materials carried in the hydrocarbon fluids. The liquid carrier can then flow into the formation or inside of the screen and up the wash pipe where it can be returned through the top port into an upper annulus area.
The service tool can then be manipulated into a “squeeze or test position” in which a seal above the top port is sealed in a packer assembly to stop return flow and force the fluid that is pumped downhole into the formation. The packer can be tested using pressure in the upper annulus.
The service tool can also be manipulated into a “reverse-out position” in which the top port and the crossover port are repositioned to be above the packer. Fluid circulation can occur at the top of the packer, either forward (e.g. down the work string) or reverse (e.g. down the upper annulus). The completion assembly can include a reverse ball check that can prevent fluid losses down the wash pipe into the formation. The service tool is then removed from the bore and the bore is prepared for installation of an uphole production tubing assembly.
Although effective, such implementations require at least two trips downhole—one to set the sand control screen via a work string, and a second to run a production tubing assembly. Furthermore, mechanically positioning the service tool accurately can be difficult, particularly at great depths, such as 25,000 or more feet below sea level, and at high wellbore angles. In addition, components such as a service tool, an upper extension, a closing sleeve, and a casing, may be subjected to erosion during sand control pumping, or otherwise may experience erosion and fail to function properly.
Therefore, assemblies are desirable that can reduce the number trips downhole, facilitate downhole positioning, and/or decrease effects of erosion in a downhole environment.